In a physical layer hybrid automatic repeat request (HARQ) procedure, a User Equipment (UE) monitors a High Speed-Shared Control Channel (HS-SCCH). If no data is received, the UE has no action, which can be understood that: the UE does not transmit information to a base station (a Node B), and in this case, feedback information acquired by the Node B is Discontinuous Transmission (DTX) information. If data is received, data on a High Speed-Downlink Shared Channel (HS-DSCH) is detected according to control channel information. If the received data is correct, acknowledgement (ACK) information is transmitted to the Node B; if the received data is incorrect, Negative acknowledgement (NACK) information is transmitted to the Node B. The DTX, ACK, and NACK information are uniformly referred to as hybrid automatic repeat request-acknowledgement (HARQ-ACK) information. After being encoded, the HARQ-ACK information is further transmitted to the Node B through an uplink High Speed-Dedicated Physical Control Channel (HS-DPCCH). The Node B receives and translates the feedback information. If the feedback information is ACK, new data is transmitted; if the feedback information is NACK, the data is re-transmitted; if the feedback information is DTX, the new data is re-transmitted.
In the Third Generation Partnership Project (3GPP) standards, a Dual Carrier-High Speed Downlink Packet Access (DC-HSDPA) technology is introduced for improving user experience. Based on the technology, several HARQ-ACK encoding solutions are provided in the prior art, and are specifically illustrated as follows.
In the Release 5 (R5) version of 3GPP TS25.212, a single-carrier encoding solution is provided. In this case, a total of three feedback signals are required to be transmitted, namely, ACK, NACK, and DTX, in which ACK and NACK are required to use codewords, as shown in Table 1-1:
TABLE 1-1Single-Carrier HARQ-ACK Encoding SolutionACK1111111111NACK0000000000
In the Release 8 (R8) version of the 3GPP TS25.212, a dual-carrier encoding solution is provided, and the solution requires nine feedback signals, in which eight codewords are used (DTX does not use any codeword), as shown in Table 1-2:
TABLE 1-2Dual-Carrier HARQ-ACK Encoding SolutionThe UE only detects data block on a primary carrier.ACK1111111111NACK0000000000The UE only detects a data block on an secondary carrier.ACK1111100000NACK0000011111The UE detects data blocks on both of primary and secondary carriers.Primary carrierSecondary carrierfeedback signalfeedback signalACKACK1010101010ACKNACK1100110011NACKACK0011001100NACKNACK0101010101
Currently, researches about Ternary Cell (TC) technologies have not been started yet, and the inventors find by studying the prior art that: if the prior art is adopted to solve the feedback problem in TC, the most direct method is to adopt three code channels, each carrier uses one code channel, and then the encoding solution as shown in Table 1-1 is adopted; or two code channels are adopted. One carrier uses the encoding solution as shown in Table 1-1, and the other two carriers use the encoding solution as shown in Table 1-2. Disadvantages of the two methods lie in that, excessive power is required to be consumed, the generally consumed power is 2 to 3 times of that for the single carrier, and a system Cubic Metric (CM) value is increased, thus affecting the system performance.